Electric switching apparatus



w. scHwE TzER ELECTRIC SWITCHING APPARATUS Filed Oct. 29, 1928 May 5, 1931.

/hvenom Patented May 5, 1931 PATENT OFFICE i Y l WILHELM SCHWEITZER, OF DUISBURG, GERMANY :1 v ELECTRIC SWITGHING APPARATUS Application led October 29, 1928, Serial No. 315,832, and in Germany October 22, 1927.

1 rlhis invention relates to an electric switching apparatus with two contacts rolling on each other, in which the contact giving-surfaces are moved uniformly and positively 5 and are arranged eccentrically to rotatable laxles spaced from each other and mounted sothat they can be moved towards each other,-said contacts being pressed by means of springs or counter weights for the proinduction ofthe necessary contact pressure against each other independently of the bearingV point. The interruption spark which might be produced at the breaking of circuit when the axles are horizontal, being energeticallyblown 0E by the movable contacts after the manner of the action of the horns, the interrupting being accelerated as between the contact paths a refractory stationary or movable partition is arranged by which the v switch spark is subdivided directly at the production and broken instantaneously. On theaxles which are spacedand mounted so that they can be moved towards each other several segments rolling on each other are iixed, which are rotated simultaneously and uniformly for closing and breaking the circuit, and which have eccentric or concentric running surfaces so that, with springs loosely mounted on the axles and with eccentric running surfaces of the segments, these segments effect, at the circuit closing movement the tensioning of the springs from the f starting of the circuit closing position to the production of the contact pressure the circuit breaking movement being eifected by the expanding of the additional expansion of the springs, while, if the springs are attached to levers fixed on the spaced and mutually movablev axles, said levers being situated in the a circuit closing position a certain angle below the -imaginary line connecting the axle centres and in the circuit interrupting positiona certain angle above this imaginary .n l connectingline, so that they exert, with the exception ofthe middle position, permanently a turning moment upon the axles, eccentric running surfaces of the segments as well as concentric running surfaces of the segments may be used.

i A"On the first portion of the switching travel the circuit closing movement is accelerated, as the springs must first expand and at the further circuit closing movement a putting on of the magnet core freefrom shocks is pro-duced by the pressing of the springs u while at the circuit breaking the pull springs accelerate the interrupting movement and are again put under tension during the last portion of the switching travel so that they produce a braking effect which delays the stroke of the electromagnet so that, the springs being permanently under tension, the interrupting movement is limited without stop.

The switch according to the invention differs from the switches of known type in that the contact surfaces are arranged eccentrically on their pivot axles and the spaced axles adapted to move towards each other are controlled by the pull of springs or counter weights, whereby the contacts carry out two movements simultaneously and create automatically at the circuit closing their heavy pressure required for the extreme position independently of the switch mechanism, in separating the circuit closing and circuit breaking position of the contactsY from the permanent position of the same and produce the maximum switching speed at the moment of the circuit breaking. 80

An embodiment of the invention is illustrated by way of example in the accompanying drawing, the running surfaces of the segments extending concentrically.

Fig. 1 shows the switch in the circuit clos- 85 ing position in a section on line A-B-CD of ig. 3.

Fig. 2 shows the circuit breaking position of the segments with the contacts. p

Fig. 3 shows on one half the apparatus in 90 top plan view and on the other half a central section.

On the axles 2, mounted parallel and guided movably at a certain distance from each other in the bearings 1 open at the inner ends, the 95 segments 3 are keyed which have each a contact block 4. The segments 3 shown on the drawing have concentrically extending running surfaces 5. These surfaces might however be eccentric. The contact blocks 4 30 are secured by means of spring-controlled contact bolts 7 in holders 6 projecting laters ally from the segments. The elastic mounting of the contacts 4 in the direction of the 5 contact pressure is obtained by the interposition of springs 8, the rigid connection of the bolts 7 to the contacts 4 and to the leading out wires 9 remains. The bearing surfaces 10 (Fig. 3) of the contact blocks 4 bear- 10 ing against the holders 6 are rounded accordingly for the adjusting movement, and the contact bolts 7 have so much clearance in the holders 6 that at the switching proceeding the Kcontact blocks bear automatically and instantaneously on their entire contact surface, as only the moderate holding pressure of the springs 8 amounting to a small fraction of the bearing pressure has to be overcome, the elastic mounting of the conmj, tacts 4 having no influence on the contact pressure itself. In the other sides of the segments 3 bolts 11 are arranged in such a manner that in the circuit closing position they form with the imaginary connecting line of 25, the axle centers and angle a and in the circuit cutting position an angle ,8, so that the entire switch angle is :a-t. To these bolts 11 pull-springs 12 under tension are attached. By this arrangement the pull springs l2 are so. expanded at the circuit breaking on the travel 13 double the distance 14 plus the eccentricity ofthe contact surfaces 15, whereby the circuit breaking speed is accelerated, while on the travel 16 beyond the imaginary line connectasing the axle centres the pull-springs 12 are again put under tension double the distance 17, so that shortly before the extreme circuit breaking position the switching speed is reduced. By-the accelerated circuit breaking 4g; movement the contacts 4 are rapidly moved away from each other whereby the switch ing spark is energetically broken, while by thedelayed extreme switching movement a putting on of the magnet core free from 451 shock is ensured. At the circuit closing the pull'springs are inversely expanded first on the travel 16 double the distance 17 and then put under tension on the travel 13 double the distance 14 beyond the amount of veccentricity 'of the contactrsurfaces at the last moment ofthe switching movement, whereby the initiating switching movement of the electromagnet is assisted, while the tension of the springs by twice the travel 14 plus the eccentricity of the contact surfaces takes place at the last moment of the circuit closing movement and the magnet core is put on free of shocks. To shorten the duration of the switching spark the Y ga between the 6o. contact travels is filled by are ractory partition 18, by which'the switching spark is subn divided and broken as soon as produced. The rotary movement of the axles 2 for the uniform circuit closing and breaking is effected from the rod 19 of the electromagnet through the intermediary of a transverse bar 2O rigid with said rod 19, the crank pins 21 of shaft 2 and rollers 22 rolling in slots 23 of said transverse bar. The action of the pull springs 12 can be increased by an according arrangement of counter weights 24. The terminals 9 for the conductors are arranged in the extension of the central lines of the axle 2, in order that at frequent switching operations the conductors are moved as little as possible.

I claim 1. An'electric switching apparatus, comprising in combination two rotary axles spaced from each other and movable towards each other, two Contact elements rolling on each other, contact surfaces in said contact` elements eccentric to said axle, springs adapt ed to press said contact surfaces against each other for producing the required contactv pressure independently of the bearing point said movable contacts breaking energetically after the manner of the action of horns the interrupting spark produced when said axl are horizontal, and a refractorypartition al'- ranged between ,the contact paths to meelthe tension ofsaid springs at the circuit break-A ing position being increased at the circuit closing 4movement; up to the production of the Contact pressure so that the circuit break-v ing movement is effected by the expanding of additional spring tension.

3. An electric switching apparatus, coni-l prising in combination two horizontal axles rotatable. and movable towards each other,

segments having eccentric running surfaces mountedon said axles, levers one for each segment fixed on said axles, spiral s ringsv attached one at each segment and at t e corf responding lever, said levers being situated in the circuit closing position an angle a below the imaginary connecting line betweeny the axle centres and in the circuit breaking v position an angle above said imaginary connecting line so that thev circuit breaki movement is limited without stop andsai springs remain permanently under tension.

4. An electric switching apparatus, Oomprising in combination two horizontal axles, contact segments mounted on said axles, a contact block on each segment, a holder for each contact block, a bolt rigid with each of said Contact blocks and elastically mounted in each of said holders, a connection terminal rigid with the outer end of each of said bolts ves so that the contact surfaces of said blocks adjust laterally automatically on the entire switching travel over the entire contact width without influencing the contact pressure.

5; An electric switching apparatus com prising in combinationtwo horizontal axles segment shaped contact elements on said axles, an elastically mounted contact block on each of said segments, connecting terminals one for each segment rigidly connected to said contact blocks and situated in the extensions of the central lines of said axles.

In testimony whereof I aix my signature.

WILHELM SCHWEITZER. 

